Citing an anonymous source, South Korean newspaper JoongAng Ilbo reported that the victims were killed in seven cities across the country on Nov. 3. Around 10 people were executed in each place, the daily said.

Its report said that in one instance eight people were brought into a local stadium with their heads covered in white bags before being gunned down by a firing squad. The stadium was supposedly filled with some 10,000 onlookers who were forced to watch the execution, the paper's source alleged, claiming to have spoken to eyewitnesses.

"I heard from the residents that they watched in terror as the corpses were (so) riddled by machine-gun fire that they were hard to identify afterward," the source told JoongAng Ilbo.

According to the source, those executed were accused of offenses including possessing forbidden South Korean DVDs, "sexual misconduct" or distributing pornography — the same charge used against a former girlfriend of the North Korean leader who was allegedly executed in August.

The crackdown, if confirmed, could signal a wider campaign to quell public unrest.

The JoongAng Ilbo noted that the executions happened in cities where the government is trying to earn hard currency through schemes like tourist resorts and ski stations.

A website run by North Korean defectors said its sources had heard rumors several months ago of plans to carry out public executions as a means of enforcing Kim's authority, according to Agence France-Presse.

"The regime is obviously afraid of potential changes in people's mindsets and is pre-emptively trying to scare people off,'' one of the website's officials told the news agency.